The present invention relates, in particular, to the manufacture of tires, and more particularly, to the manufacture of reinforcement armatures, such as those which are present below the tread of belted tires, the carcass of which is generally radial.
Such reinforcements have been manufactured in the form of semi-finished products known as "plies" which were prepared flat and then incorporated in the assembling of the article. U.S. Pat. No. 4,952,259 relates to the producing of such reinforcements from a continuous thread and placing them directly on the tire blank. This proposal is based on the projecting of a thread in the manner of the thong of a whip.
FIG. 1 illustrates an apparatus for the manufacture of a tire reinforcement employing this principle. Such an apparatus uses a thread 1 fed, for example, by feeding means from a spool, not shown. The apparatus projects lengths 10 of said thread onto a receiving surface S which in this case is part of the tire being manufactured.
The expression "thread" is used herein in a very broad sense to include a monofilament, a multifilament, a cable, a twist or an equivalent assembly, and this whatever the material constituting the thread or the treatment which it has undergone, for instance a surface treatment in order to favor its intimate bonding to rubber, or a rubberizing treatment surrounding said thread with a layer of rubber in order to permit its direct adherence on the support upon its projection.
The apparatus is an assembly 5 which includes:
means for advancing the thread 1 from a source of thread (not shown), such as a spool, PA1 a rotary conduit 2 mounted on a shaft 20 constituting the axis of rotation of said conduit, in such a manner that the outer radial end 21 of said conduit is directed substantially radially with respect to the axis of rotation, said conduit receiving the thread 1 at its central end 22 opposite said outer radial end 21 coming from the thread feeding means, said thread emerging through said outer radial end, said feeding means controlling the linear speed of advance of the thread within said rotary conduit, PA1 means for driving said rotary conduit 2 in rotation, PA1 means for cutting the thread in such a manner as to free one length upon each rotation of said rotary conduit 2.
Furthermore, said apparatus comprises a thread guide, designated generally as 4, for receiving lengths 10 of thread. For further details as to the operation of an apparatus of this type, reference should be made to U.S. Pat. No. 4,952,259. In that apparatus, the thread guide 4 is positioned with respect to said rotary conduit 2 in such a manner as to receive the thread, or more precisely lengths 10 removed one after another from this thread, in the plane of rotation of said conduit 2. The thread guide 4 receives each length 10 of thread, which passes through this thread guide and emerges through a projection orifice 40 in the immediate vicinity of the surface on which the length of thread is to be deposited and held by adherence. In a preferred embodiment of the apparatus, the lengths of cords are whipped and forced through the thread guide.